when adding bike lanes actually reduces traffic delays

Posted On Friday, 28 August 2015

Almost everyone agrees on defining the Level of Service (LOS) as a good measure, however, California is replacing this LOS for Vehicle Miles Traveled (VMT). Under the LOS system, a proposed bike lane had to analyse its
transportation impacts and if it was found to slow down cars (by, say
substituting a bike lane for a car lane) then the California's environmental statute
would have said let’s either not build this project, or pay a lot of
money to find some other way to speed up cars.

So what happened here to overcome the traditional idea that bike lanes lead to car delay? No doubt many factors were involved, but the steady traffic flow was largely the result of adding left-turn pockets. In the old street configurations, cars turned left from a general traffic lane; in the new one, they merged into a left-turn slot beside the protected bike lane. This design has two key advantages: first, traffic doesn't have to slow down until the left turn is complete, and second, drivers have an easier time seeing bike riders coming up beside them.